Are book tags a threat?

Once upon a time, checking out an armful of library books could seem to take longer than writing them yourself. Today, however, using the technology that lets commuters zip through E-ZPass tolls, some libraries are offering quicker checkout, improved inventory practices, and better protection against theft.

But privacy advocates are already opposing use of radio frequency identification (RFID) in libraries.

As RFID technology becomes more advanced, they warn, it could allow both the tracking of books borrowed by a reader and the tracking of the reader via his library books. This could permit the government or other interested parties to compile a list of readers who have checked out books on particular topics - a potential invasion of privacy that civil-rights advocates find troubling.

About 250 libraries nationwide - including several college libraries - already use the technology. In San Francisco, however, where the Public LIbrary Commission is moving forward with plans to use it in city libraries, the American Civil Liberties Union petitioned the city to withhold funding of the project until privacy risks could be more accurately determined.

RFID technology works by placing a thin, inch-square tag on each library item. The tags electronically store information, such as an identification number or a book's title and author. The data are accessed by RFID readers, which activate the tags by emitting radio signals and then reading information on the tag using a transceiver and decoder.

This makes it possible to take inventory of an entire shelf in a matter of seconds. A stack of books can also be checked out rapidly, without opening each cover and scanning bar codes - making self-checkout an easy option.

While the system is significantly more expensive than bar-coding systems (each tag costs between $0.50 and $1.00) it can cut libraries' costs substantially. The efficient inventorying system can turn up tens of thousands of dollars' worth of lost books, while the self-checkout capability can cut labor costs.

Right now, says David Wagner, a computer science professor at the University of California in Berkeley, "the risk exposure is very low." Together with David Molnar, a graduate student at the University of California at Berkeley, Mr. Wagner studied the privacy and security of library RFID systems, focusing primarily on potential future risks.

If RFID readers started using larger, more powerful antennas, the tags could be read from much farther away than the one- to three-feet range within which they currently operate. But Wagner is more concerned with the fact that anyone with an RFID reader - which costs about $200 - could access the data on at least some tags.

What Wagner envisions, however, is the development of a "smart tag" that could be read only by the library's own RFID reader. This, Wagner believes, could be the key to benefitting from RFID technology without compromising patrons' privacy.